Machine for tensioning and winding wire onto pipe



mmw MZ Aprxl 23, 1968 P. O'SWEILER MACHINE FOR TENSIONING AND WNDINGWIRE ONTO PIPE Filed Sept. E,

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Unied States Patent O 3,379,385 MACHINE FOR TENSIONING AND WINDiNG WIREGNT() PIPE Paul L. Osweiler, Dayton, Ghio, assignor to Price BrothersCompany, Dayton, Ohio, a corporation of Michigan Filed Sept. 3, 1965,Ser. No. 484,936 3 Claims. (Cl. 242-11) ABSTRACT F THE DHSCLGSURE Amachine for prestressing cable and winding it onto a concrete pipe byvertically supporting it on a shaft coaxial with a capstan and threeelement gear differential. A first motor reciprocates a wiredistributing guide and rotates the pipe, shaft and planetary gears ofsaid differential while a second motor rotates the sun gear of thedifferential at a speed regulated by a cable guide responsive to thetension and thus elongation of the cable. The cable is unwound from asupply, wrapped for several turns about the wire tensioning capstanconnected to the ring gear of the differential, led over the tensionresponsive guide, then over the distribution guide to be connected tothe pipe so that speed of rotation of the pipe is regulated to maintainconstant tension in the cable.

This invention relates to means for winding tensioned strand over largepipe and particularly for working with heavy steel strand over largesize pipe for prestressing. Pipes of steel or concrete or both havingdiameters as large as 12 feet and even more are reinforced by windingtensioned steel strand as a helix over such pipe. While the stranddiameter and helix pitch may have a variety of values, depending uponthe pipe design, a pipe length may have as much as 4 miles of strand andthe strand size may be as great as about 3yrs-inch in diameter ortransverse dimension. The strand tension during winding may be about 75%of ultimate and the pull on the strand may be in the order of about15,00%` pounds.

Concomitantly with the creation of strand tension is strand elongation.With the steels used in this art and the tensions employed, strandelongation of about 1% results. Thus, strand elongation of between about100 and 200 feet for a complete pipe length may be expected.

In addition to the above, the economics of pipe manufacture requireshigh speed handling of strand, as much as about i560 feet per minute,initiation of winding at either pipe end, temporary cessation of awinding operation without loss of tension, rapid adjustments toaccommodate different pipe sizes, different strand sizes and tensions,different strand pitches and to do all these with minimum labor.Collateral to the above what may be termed operating economics, is thefixed investment factor of land or horizontal space required forconventional application of tensioned strand to pipe. Conventionaltensioning means for taking up as much as 200 feet of added strandgenerally requires substantial horizontal space, the take-up in avertical direction being too costly as a rule. Furthermore, suchconventional tensioning and winding procedure and means are inherentlyinefficient and time-consuming.

The invention hereinafter set forth provides a means and method basedupon a novel concept and makes it possible to operate efficiently athigh speed and within a physical space which, in comparison to presentapparatus and technique, is relatively small. The present inventionutilizes a differential gear mechanism for strand elongation take-up.Substantially untensioned strand is fed to ICC a capstan, about which anumber of strand turns is made for strand holding. From the capstan, thestrand is guided to be wound under tension about the surface of a pipeto be reinforced. Strand tension is created by the operation ofdifferential mechanism governing the relative speeds of rotation ofcapstan and pipe. Strand elongation take-up in such a system involvesangularity instead of length as a variable parameter.

A differential gear mechanism basically involves three components; a sungear, a ring gear and a planetary gear assembly (one or more gears andthe arms or the like for supporting purposes). Positive power may be fedto one component, positive or negative (as braking) may be fed toanother component and the third component can provide power. The powerin each case involves angular velocity ratios (due to the meshing actionof gears) and as a result makes it possible to obtain an overalldifferential operation which fulfills the needs of strand tensioning andwinding as hereinbefore set forth. In the new system, positive power issupplied to two differential components and the selection of particulardifferential components for driving capstan and pipe respectivelyresults in a system having decided advantages.

The new system includes introduction into the path of power flow oflocking means to prevent potential energy stored in strand tension,during stoppage of winding, from backing up through the system andrelieving the tension. Additionally, pitch control means are disposed ina power flow path to the pipe rotating means to maintain a desired ratioof pipe rotation and strand feed along the pipe.

An advantage of the system having two power inputs to the differentialmechanism is that quick changes to accommodate differential pipediameters, lengths, strand tensions rnay `be made. Furthermore, accuratetension control is obtainable in the new system utilizing a differentialgear mechanism, apart from the number of power inputs. Thus, the newsystem has means responsive to tension of strand between the capstan andpipe for controlling differential action. Such a control is continuousand monitors the system to prevent substantial tension variations.

In the system illustrated here, the pipe being wound is coupled to theplanetary gear assembly and the two have a main power input. A secondand smaller power input is provided to the sun gear. The ring gear iscoupled to the capstan. This coupling pattern makes possible a compactphysical arrangement wherein the pipe and capstan can be yco-axial, turnin the same direction and strand feed and control are simplified. Theinternal forces oppose each other and reduce the overall powerrequirements.

The Imain power input to the pipe and planetary gear assembly takes careof power requirements for starting and winding generally. This mainpower input also functions to some degree to ten-sion the strand, muchof the power input under running conditions being used for that. Thering gear, which is coupled to the capstan, receives power therefrom asthe result of the strand drivin-g the capstan. The second power input tothe sun gear is controlled by strand tension responsive means andprovides `an over-riding force for strand tension control. This effectis obtained by controlling the relative peripheral speeds of strandleaving the capstan and going on to the pipe.

The second power input to the sun gear is through a one way power drivewhich permits power flow toward the sun -gear 4but prevents reversepower flow away from the sun gear. Thus, strand tension relief isprevented during stoppage of winding.

The physical larrangement of differential gear mechanism and associatedcapstan and pipe support is such that all parts rotate with or around ashaft which can be vertical and heavy enough to be stable `and wellsecured. The relative sizes of the two power input sources may varywidely. In general, the main power input to the pipe turntable andplanetary gear assembly should be great enough, in comparison to thesmaller power input to the sun gear, so that the action of the lattershould have no substantial effect on the main power input insofar aspipe winding speed is concerned. Theoretically, the dierential couplingbetween the two power inputs may cause some instability due to feedback. In practice, the frictional resistance in the entire system,including the power sources land capstan drive, substantially eliminatesinstability due to coupling between power sources through theditferential mechanism.

In order that the invention may be understood reference will now bevmade to the drawing illustrating a system embodying the invention.

Base has vertically disposed shaft 11 extending upwardly therefrom Iandrotatable therein. In practice the base will be a massive structurecontaining suitable bearings and heavy enough to support the variousparts. Shaft 11 is of steel and may be solid or in the form of a heavypipe. For ease of `assembly and transport to a location, shaft 11 mayconsist of a number of separate lengths suitably coupled together. Itwill therefore ybe understood that shaft 11 includes any extensionswhich may normally be required in a large structure of the general typedisclosed herein.

Disposed about the lower portion of shaft 11 and rotatable with respectthereto is capstan 12 which may be dimensioned and shaped for handlingthe size strand used. In practice, capstan 12 may be one of two or threesuperposed capstans of various sizes rigidly secured together and havingdifferent diameters and faces for handling various pipe sizes. Capstan12 accommodates a plurality of turns 14 of steel strand 15. Strand 15comes from a suitable supply source having one or more reels andprovided with suit-able means for imparting a llow initial tension tothe strand to prevent reel unwinding and snarling. It is understood thatstrand portion 16 leaving capstan 12 will be under `desired tension forwinding upon a pipe.

Capstan 12 is secured to `housing 20 extending upwardly from thecapstan. Housing 2) has secured thereto ring igear 2]. at the upperinterior portion. Meshing with the teeth of ring gear 21 are planetary`gears 23 rotatably supported in frame 24 which, in turn, is secured torotate with shaft 11. Frame 24 lrnay have .as many planetary gears 23 asare necessary to carry the load.

Planetary `gears 23 also mesh with sun gear 26 which is rotatable aboutshaft 11. Sun gear 26 is rotatively secured to sprocket 27 so thatrotary power may be fed to the sun gear. The ring gear, planetary gearsand sun gear form a differential gear assembly.

Rotatively secured to shaft 11 is main drive sprocket 30 for receivingpower to rotate shaft 11. Disposed above the top of shaft 11 androtatively coupled thereto is turntable 33 for supporting a length ofpipe 34 to be wound with tensioned strand. Turntable 33 would, inpractice, be supported on heavy bearings and the entire turntable andpipe would be supported by heavy stationary framework independently ofshaft 11. In addition, various parts of the ditferential would beprovided with suitable bearings to reduce friction and support partsproperly. Suitable means for lubrication will also be provided.

Turntable 33 is provided with centering blocks 36 which may be adjustedfor various pipe sizes to enage and center the inside end of pipe 34.The top of pipe 34 is supported by hold down plate 38 which may beprovided with centering blocks 39 generally similar to centering blocks36. Hold down plate 38 is supported from cantilever arm 40 which ispivotally secured at 41 to slide block 42 supported for verticaladjustment on guideways of stationary vertical structure 43. Structure43 can be adjusted to accommodate various lengths of pipe and be lockedin position.

'Block 42 is provided with means for raising top plate 3S as shown inthe dotted line position. Toggle arms 45 and 46 are pivoted respectivelyat 48 and 49 to arm 40 and block 42. The knee of the toggle is at pivot50 and this is connected by rod 51. to a piston in air cylinder 52. Tomove top plate 38 clear of the top of pipe 34, cylinder 52 is energizedto break the toggle and pull toggle pivot 5) toward block 42. Any othermeans for removing top cover 38 from the top end of pipe 34 may beprovided. The removal of top plate 38 permits the removal from orpositioning on, the turntable, as the case may be, of pipe 34. Inaddition, top plate 38 and the remainder of the structure forcontrolling the position of top plate 38 provides a retaining force forthe top end of pipe 34 to maintain the pipe rigidly in position duringwinding.

Referring now to capstan 12, strand 16 leaving the capstan is guided totension sheave 60 Whose axle pin forms part of clevis 61, which in turnis secured to a piston rod carried by piston 62. operating in aircylinder 62A. Air cylinder 62A is securely anchored to a stationarymember and has air supply pipe 63 connected to the piston rod end ofcylinder 62A andis connected through automatic air pressure control 63Ato a suitable source of compressed air. The air pressure in cylinder 62Awill determine the position of piston 62. and can thus, within limits,control strand tension. Air pressure control 63A can be set to maintainquite accurately the air pressure in cylinder 62A. This control willtake care of momentary tension drops due to strand slippage on thecapstan. Pipe 63 has pressure relief valve 63B to reduce momentarystrand tension rises by permitting air from cylinder 62A to exhaust tothe atmosphere when pressure rises. Pressure relief valve 63B can beused to disable the tension maintaining means and permit sheave 60 tomove correspondingly.

The above arrangement for tension control is useful only for transienttension control. For continuous tension control and strand take-up,clevis 61 is coupled to potentiometer wiper 64 cooperating with resistor65. The objective of the entire strand tension maintaining means is toobtain an electrical potential (or current) which is a function of theposition of the piston in the cylinder and thus a function of the strandtension.

:Potentiometer resistor 65 is connected by wires to a suitable controlmeans in a variable speed motor drive system generally indicated by 67.The drive system includes electric motor means and vvariable ratiotransmission for obtaining a desired power output. Drive system 67 isconnected through one-Way drive 63. One way drive 68 is of the typewhich will transmit rotary power to sprocket 69 but will not permitpower to flow back from sprocket 69 to the motor drive system,irrespective of the direction of rotation. An example of a one-way drivedevice that can be used is a so-called R L Clutch manufactured and soldby Formsprag Company of Detroit, Mich. Such one-way drives are used inautomotive vehicles to prevent road shock from being transferred back tothe steering wheel, cutting tool machinery to keep a cutting tool inposition against work, and elsewhere. Other devices, electrical,mechanical, or hydraulic may be used for obtaining the one-way driveaction.

It is understood that the potentiometer control may be replaced by othertension responsive means for controlling variable motor drive 67. Theone way coupling 68 is provided to maintain strand tension during workstoppage and prevent tension relief through the differential. Motordrive 67 will operate to take up excess strand length during winding andmaintain a substantially constant strand tension during the take-up.

Returning now to strand 16 at sheave 60, the strand continues to guidesheave 70 which directs strand 16 vertically, parallel to but laterallyoffset .from the axis of pipe 34. Strand 16 goes from guide sheave 70 topayout sheave 72 from where the strand is fed to the outer surface ofpipe 34. Payout sheave 72 has its axle 74 supported by arms 75 and 76whose ends are pivotally secured at 77 and 78 respectively to form atrunnion. The trunnion axis is vertical, parallel to the axis of pipe 34and in line with the line of vertical travel of portion 16A 0f thestrand between sheave 70 and payout sheave 72.

The arrangement is such that payout sheave 72 can rotate about thetrunnion axis and guide strand in a direction tangent to the outersurface of pipe cylinder 34, irrespective of the diameter of pipecylinder 34. The trunnions for payout sheave 72 are supported byvertically movable carriage 79 which is guided for vertical travel alongguideway 80 of vertical support structure 43. The vertical position ofthe trunnion carriage is controlled by chain 82 extending betweensprockets 84 and 85 parallel to the pipe axis. The coupling betweenchain 82 and the trunnion carriage may be obtained in any suitablefashion by locking the two together. Chain 82 is supported to withstandthe tension of strand portion 16A.

Main power source 90 consisting of an electric motor is used for drivingsprocket 30 which is directly secured to shaft 11 for turning pipe 34.Motor 90 is coupled through variable speed transmission 91 to drivesprocket gear 92 which is connected to sprocket gear 30 by a suitablesprocket chain. Variable speed transmission 91 also drives sprocket gear95 which is connected by a sprocket chain to sprocket gear 96. Sprocketgear 96 is connected through variable speed transmission 97 to oneelement 98 of clutch 99. Clutch 99 has selector portion 100 which may beselectively coupled to clutch element 98 or clutch element 101. Selectorelement 100 of clutch 99 is connected to drive bottom sprocket gear 85which drives chain 82. Clutch element 101 is connected through gears andsprocket chain 103 to auxiliary motor 105.

The objective of the above arrangement for driving chain 82 is to obtaina desired chain speed in either direction while pipe 34 s rotating or topermit chain 82 to be driven independently of pipe 34 so that thecarriage may be moved without necessarily having the pipe turntable andstrand feed operating. As a rule, auxiliary motor S will be used forvertical carriage adjustment prior to strand tensioning. It isunderstood that auxiliary motor 105 can be controlled to drive the chainin either direction. Also variable speed transmission 91 in the powertake olf from main motor drive 90 to sprocket gear 30 will permit thetravel of chain 82 to be reversed, as for example when beginning to winda pipe, so that the principal control for main drive motor willautomatically operate the pitch control carriage in a desired directionand at a desired speed to obtain a desired strand pitch.

Limit switches may be provided for stopping the flow of power from mainmotor 90 to sprocket gear 30 when the pitch control carriage has reacheda top or bottom limit position. Reversing switches may also be providedfor reversing the direction of carriage travel after the carriage hasreached a predetermined top or bottom strand winding position.

No attempt is made to show the relative magnitudes of main power drivemotor 90, auxiliary motor 105 or variable speed differential motor drive67. As a rule, main motor drive 90 should have a substantially greateramount of power available than variable speed motor 67. This is on theassumption that fast starting of strand winding and substantial windingspeed, such as about 1500 feet of strand per minute are desired. Insofaras variable speed diflerential motor drive 67 is concerned the powerrequired to provide suitable differential action for strand tensioningwill depend in some degree upon the speed of winding. Thus in apractical machine for handling 3As-inch strand on pipe ranging up to 12feet in diameter with a winding speed of about 1500 feet per minute,main motor drive 90 was 125 horsepower whle the motor drive fordifferential action 67 had a maximum rating of 50 horsepower.

It is undestood that the above figures represent maximum power ratingsconnected through suitable speed reduction means to accommodatedifferent size strand on different size capstans for different sizepipe. The direction of power feeds to the pipe and sun gear are arrangedso that the pipe and capstan both turn in the same direction. Whenstarting to wind a pipe the following procedure may be adopted. Assumingthat the leading end of the strand is suitably anchored to the pipe, andbefore the main power drive for turning the pipe comes on to turn pipe34, automatic air control 63A can be turned on to move sheave 60 andcreate tension in the strand. Then the drive for turning pipe 34 forstrand winding can be started. When a pipe has been wound and thetrailing strand end has -been anchored to the pipe, the main anddifferential power sources are disconnected from the loads (pipe 34 andsun gear 26) or arranged in a non-driving condition. Then the airpressure in cylinder 62A may be relieved to eliminate strand tension,after which the steel strand may be severed from the traling strand endon the pipe.

What is claimed is:

1. In a mechanism for winding tensioned steel strand in helical formabout a cylindrical pipe of concrete or the like, a shaft, means forsupporting said pipe coaxially with said shaft and coupled thereto forrotation therewith, a sun gear disposed over said shaft in coaxialrelation therewith and rotatable with respect thereto, a spider frameover said shaft and coaxial therewith and coupled to rotate with saidshaft, a plurality of planetary pinions supported on said spider framefor rotation about axes parallel to and laterally offset from the shaftaxis, each planetary pinion meshing with said sun gear, a yring gearcoaxial with said shaft disposed around and meshing with said planetarypinions to provide a planetary spur gear type of differential, a capstansecured to said ring gear, said capstan and ring gear being rotatable asa unit about said shaft, said capstan normally having plurality ofstrand turns therebout for developing strand tension during winding, afirst idler for guiding tensioned strand to said pipe surface, means formounting said first idler to be movable along a straight path parallelto but laterally offset from the pipe axis for providing winding pitch,means acting on strand extending between capstan and first idler tocreate predetermined strand tension, a lirst motor, means coupling saidrst motor to said shaft at a region laterally offset from saiddifferential to drive said shaft for pipe rotation to pull strandthereon, means for deriving power from said Afirst motor for moving saidfirst idler mounting means, a second motor, means including a toothedmember about said shaft coaxial therewith rigidly secured to said sungear and laterally offset therefrom for coupling said second motor todrive said sun gear for rotating the same to take up added strand lengthdue to tension and means responsive to said strand tension creatingmeans for controlling the speed of said second motor to maintain saidpredetermined strand tension in connection with strand length take-up,said construction having the torques incident to differential operationcontained within the differential gears and shaft with pipe and capstanrotating in the same direction for minimizing differential activity andhaving minimum number of gears, whose tooth dimensions may be easilyproportioned to obtain proper loading without load distribution and gearteeth engagement problems, said construction being mechanically simpleand readily susceptible for heavy duty high speed winding.

2. The mechanism according to claim 1 wherein a one way drive isdisposed n the coupling between the second motor and the toothed member0n the sun gear whereby when winding is interrupted, said strand tensionreacts on the differential to keep the capstan and pipe from moving toreduce strand tension.

3. The mechanism according to claim 2 wherein the shaft is vertical withthe pipe adjacent the top end of said shaft, the dilerential and capstanare below said pipe, and wherein the power couplings to said shaft andto said sun gear toothed member include sprocket chains extendinglaterally from the shaft axis, said arrangement permitting tensionedstrand from the capstan tension strand 5 to the pipe and tensionedsprocket chains to extend transversely of the shaft in desireddirections, the bottom shaft portion being available for good bearingsupport, said entire construction permitting minimium shaft length andnot requiring precision vertical positioning of the dierm ential gearcomponents for tooth engagement.

References Cited UNITED STATES PATENTS Bronander 74-675 Neugebauer74-675 X Heinz 242--' 75.5

Kennison 242--11 Dutro et al 242-755 X Szulc 242-11 BILLY S. TAYLOR,Primary Examiner.

